The hacker BestBuy pleaded guilty in court on Friday to hijacking more than 900,000 routers from the network of Deutsche Telekom.

The notorious hacker BestBuy, also known as Popopret, pleaded guilty in court on Friday to hijacking more than 900,000 routers from the network of Deutsche Telekom. The 29-year-old man, whom name wasn’t revealed by authorities, used a custom version of the Mirai IoT malware.

BestBuy was also known as the author of the GovRAT malware, he offered the source code of the RAT, including a code-signing digital certificate, for nearly 4.5 Bitcoin on the TheRealDeal black market.

German authorities referenced the man as Spiderman which is the name he used to register the domain names that the hacker used as C&C for his botnet.

BestBuy targeted the routers in late November 2016 with the intent to recruit them in its botnet that was offered as a DDoS for hire service, but accidentally the malicious code variant he used triggered a DDoS condition in the infected devices.

According to the German website FutureZone.de, Deutsche Telekom estimated that the losses caused by the cyber attack were more than two million euros.

“The hacker admitted in court that he never intended for the routers to cease functioning. He only wanted to silently control them so he can use them as pawns in a DDoS botnet. ” wrote Bleepingcomputer.com.

Early December 2016, the man used another flawed version of Mirai that caused the same widespread problem in UK where more than 100,000 routers went offline. The routers belonged to Kcom, TalkTalk, a UK Postal Office, TalkTalk ISPs.

BestBuy’s sentencing hearing is scheduled July 28, the man faces up to ten years in the jail.